1. Field of the Invention
The present invention relates generally to containers, and more particularly, to a method and apparatus for making plastic containers that have a finish portion that is oriented with respect to the body of the container.
2. Related Art
It is becoming more common for containers to have closures that include a feature that needs to be aligned with respect to the container body at a particular orientation. For example, a closure may have a dispenser that needs to be aligned with the front of the container body. Shampoo bottles often have such a requirement. As another example, a closure may have a spout that is preferably aligned with the handle of the container body, as is sometimes the case with detergent containers.
One known technique for orienting a closure with respect to a container body includes orienting the thread start on the finish portion of the container. In many types of blow molding operations, the threads are formed on a preform that is subsequently used to blow mold the container body. In these types of operations, the preform needs to be maintained at a specific orientation with respect to the blow mold cavity in order for the threads to hold their specific orientation with respect to the container body, once formed. Existing blow molding machines, however, allow for the preform to rotate during one or more stages of the blow molding process, thereby introducing inaccuracy into the alignment of the container body and the threads. This can ultimately result in inaccuracy in the alignment of the closure and the container body.
What is needed, therefore, is a method of orienting a finish portion on a plastic container that overcomes the shortcomings of prior art offerings.